2007年7月3日
虽然珍珠和鲍鱼贝壳的闪亮材料长期以来因其虹彩和珠宝和装饰的美学价值而受到珍视，但科学家也欣赏其他物理特性的珍珠母。
珍珠母的母亲也称为Nacre（“ nay-ker”），比阿拉贡人制成的矿物质比矿物质高3,000倍。威斯康星大学麦迪逊分校。"You can go over it with a truck and not break it - you will crumble the outside [of the shell] but not the [nacre] inside. And we don't understand how it forms - that's why it's so fun to study."
她说，了解Nacre形式的机制将是利用其力量和简单性的第一步。“我们不知道如何综合比其部分总和更好的材料。”欧洲杯足球竞彩
Writing in the June 29 issue of Physical Review Letters, Gilbert and her colleagues in the UW-Madison department of physics and School of Veterinary Medicine, the Institute for the Physics of Complex Matter in Switzerland and the UW-Madison Synchrotron Radiation Center, now describe unexpected elements of nacre architecture that may underlie its strength and offer clues into how this remarkable material forms.
Like our bones and teeth, nacre is a biomineral, a combination of organic molecules - made by living organisms - and mineral components that organisms ingest or collect from their environment. The aragonite mineral in nacre is made of calcium carbonate, which marine animals form from elements abundant in seawater.
吉尔伯特说，尽管仅有5％的鲍鱼Nacre是有机的，但这一小部分以某种方式奠定了足够的基础，可以使矿物质成分自发地组装。
她说：“该生物矿物质的质量中有百分之九十五是自组装的，而只有5％的生物体由生物体积极形成。”“这是您可以想到的最有效的机制之一。”
为了深入了解这一自组装过程，吉尔伯特（Gilbert）和研究生丽贝卡·梅茨勒（Rebecca Metzler）使用同步加速器辐射检查了鲍鱼nacre的结构 - 通过电子在弯曲轨道周围发射的电子发出的光。
当用来检查鲍鱼壳的横截面时，以前看到的类似于有机“砂浆”分离单个晶体“砖”的砖墙，同步子的偏振光表明Nacre壁不均匀。
Instead, the wall contained distinct clumps of bricks, each an irregular column of crystals with identical composition but a crystal orientation different than neighboring columns.
由于方向影响晶体发射电子的方式，“一些砖的圆柱看起来是白色的，而其他砖则看起来是黑色的，而更多的是灰色，具体取决于它们的晶体取向。”
The overall effect resembles a camouflage pattern, each roughly columnar cluster a slightly different shade.
She suggests that this mosaic architecture of nacre, with numerous non-aligned crystals, could lead to a stronger material by preventing the formation of natural cleavage planes - like those that form the facets of a cut diamond - where a single crystal can easily break. "It is intuitive that a poly-crystal is mechanically stronger than a single crystal, so perhaps that is an advantage for the animal," Gilbert says.
With this new information about nacre structure and the help of UW-Madison theoretical physicist Susan Coppersmith, the group turned to modeling to try to understand how such a structure could form.
Coppersmith说：“通过查看最终结果并将其与不同的增长模型的结果进行比较，您可以深入了解增长的实际机制。”
The group developed a model that suggests that the animal creates the organic "mortar" layers first, peppered with randomly distributed crystal nucleation, or seeding, sites.
从他们的观察结果来看，他们预测矿物晶体开始在壳内部生长并水平延伸，直到它们接触另一个生长的晶体并垂直直至击中上覆的砂浆。如果该晶体接触下一个层上的另一个散射的晶体形成位点，则应触发具有相同晶体方向的新晶体的生长，并逐渐构建不规则宽度的粗糙列。
With further experiments, the researchers hope to test and refine their model as well as examine other biominerals, such as human teeth and the nacre of other species such as pearl oysters, mussels, or nautiluses, to improve their understanding of biomineral formation and assembly.
吉尔伯特解释说：“如果您了解它的形成方式，就可以想到复制它，产生一种受自然启发的合成材料 - 一种所谓的“仿生”材料。”“如果我们学习如何利用形成机理，那么我们可以产生在影响点吸收所有能量但不会断裂的汽车。
"But from my point of view, it's most interesting because of the fundamental mechanisms of how it forms - these natural self-assembly mechanisms we are only just beginning to understand."